With the development of Internet, electronic commerce has become widely adopted. In ecommerce transactions, items of goods for sale (also referred to as commodities) are usually released and displayed in categories, so that it is convenient for a seller to release a commodity and for a buyer to search for a commodity. Existing techniques for storing and searching for commodities often require complex category structures to satisfy different viewing requirements. Adding a new way of browsing for information can be a burdensome operation that leads to increased storage load of database of the commodity transaction system.